System, Method, and Service for Tracing Traitors from Content Protection Circumvention Devices

Abstract

A traitor tracing system generates a hypothesized model of the circumvention device that models a hypothesized set of device keys compromised by the circumvention device. The system iteratively invokes a subset tracing system to identify a compromised device key until substantially all the compromised device keys in the set of compromised device keys are identified so as to disable the circumvention device. A subset tracing system generates a circumvention device model that models behavior of a circumvention device using prior knowledge and The system iteratively selects and applies to the circumvention device a test based on the hypothesized model and the circumvention device model and receives a response from the circumvention device indicating a success of the test in playing protected content on the circumvention device. The system updates the hypothesized model using the received response, the selected test, a current version of the hypothesized model, and a current version of the circumvention device model to focus the test selecting process in determining the device keys obtained from the traitor.

Description

FIELD OF THE INVENTION[0001]This invention relates to preventing piracy of digital content in a broadcast encryption system and more specifically to detecting pirated keys in a circumvention device generated by an adversary to pirate protected digital content.BACKGROUND OF THE INVENTION[0002]The entertainment industry is in the midst of a digital revolution. Music, television, and movies are increasingly becoming digital, offering new advantages to the consumer in quality and flexibility. At the same time, since digital data can be perfectly and quickly copied, the digital revolution also comprises a threat. If consumers may freely copy entertainment content and offer that content on the Internet, the market for entertainment content would evaporate.[0003]To solve this problem, several content protection schemes have been devised and are in wide use in the market. For example, DVD video is protected by the Content Scrambling System (CSS), DVD audio is protected by Content Protection...

AI Technical Summary

Benefits of technology

[0020]The task of the test selection module is to determine the next best test to submit to the circumvention device. The test selection module incorporates some measure of the informativeness of a test; for example, a measure of the information gained from the test.

Problems solved by technology

At the same time, since digital data can be perfectly and quickly copied, the digital revolution also comprises a threat.

The consequences of accidental or malicious disclosure of the long-lived secret keys are grave; loss of these secrets can lead total breakdown of the copy protection schemes the secrets support, and ultimately, to huge monetary loss for the participants of the copy protection scheme.

In the event that a device (and its keys) becomes compromised, deliberately or by mistake, it is necessary to revoke the keys of that device.

The licensing agency can then produce new media key blocks that revoke those compromised device keys such that newly released content cannot be played by the circumvention device.

However, this method has not proven to be a completely practical solution, in that the measures taken by the circumvention device might slow down the testing process.

In effect, such a circumvention device had defeated the content protection system.

The need for such a solution has heretofore remained unsatisfied.

Images